Last Friday night a local woman was walking down Polk Street, talking on her cell phone, when, according to the police, a man named Brandon C. West attacked her, ripped the phone out of her hands and sprinted away.

As he headed down the street, he must have thought the heist had gone perfectly. What he didn't know was that new technology captured everything on video. Quietly, taxicab companies in the city have outfitted roughly 700 cabs with "dash cams," video cameras that continuously record 180-degree shots out the front windshield.

Not only did a nearby Luxor cab record the suspect assaulting the woman, the Good Samaritan driver pulled over, picked her up and loaned her his cell phone to call police. The two tracked West to a bus stop while giving a police dispatcher a play-by-play account of his location. There is even video of police cars rolling up and officers making the arrest. Police say West has been charged with second-degree robbery.

The cabbie, whose name is being withheld for his safety, said he was a fan of the cameras from the beginning.

"It makes me feel much safer," he said. "And when the police check the chips, they can see what is going on. It's going to be very healthy."

"The video shows the crime happening in progress," said Officer Albie Esparza, "and we get a positive ID. It's beneficial to everyone."

A few years ago there was a bitter debate about city-installed crime cameras, which turned out to be expensive, controversial and virtually useless. But while everyone was debating, private companies were installing video cameras in store entrances, malls and coffee shops. And now they are in about half of the city's 1,500 cabs.

Civil libertarians are likely to complain about creeping Big Brother-ism, but that horse has long since left the barn.

You may remember the case of the phony parking lot attendant, who collected money at self-serve lots. Police say Fofana Mebema has a long history of pulling the scam, which often targeted tourists near Fisherman's Wharf.

Monday, Mebema was in San Francisco Superior Court to plead not guilty to a host of charges, one of which is a felony. A spokesperson for the district attorney's office says Mebema's attorney attempted to have the charge reduced to a misdemeanor, but the prosecutor pointed out that Mebema has had 15 bench warrants in the last five years, has served time in prison and county jail, and is currently charged with three separate instances of the same behavior.